Operation CHARM: Car repair manuals for everyone.

Initial Inspection and Diagnostic Overview



Air Conditioning (A/C) System Performance Test
This test measures the operating efficiency of the A/C system under the following conditions:
- The current ambient air temperature
- The current relative humidity
- The high side pressure of the A/C system
- The low side pressure of the A/C system
- The temperature of the air being discharged into the passenger compartment

Test Description
The numbers below refer to the step numbers on the diagnostic table.

1

This step determines if the A/C system has at least the minimum refrigerant charge required to operate the system without damage.

2

This step measures the performance of the A/C system.

3

This step is to allow for vehicle variations as well as high ambient temperatures.














A/C Performance Table